L. (Indian pipe, pinesap)
mycotrophic herbs, lacking chlorophyll, the entire plant variously white to
yellow or red, turning dark brown or black upon drying, glabrous to finely
hairy or glandular-hairy. Stems unbranched. Leaves reduced to lanceolate
bractlike scales, these shorter and mostly ovate toward the stem base, longer
and lanceolate to oblong-elliptic higher on the stem, mostly sharply pointed at
the tip. Inflorescences terminal racemes of 3–10 flowers or a solitary
terminal flower, nodding during development and at flowering, becoming erect at
fruiting. Flowers actinomorphic, perfect, hypogynous, bracteate, stalked. Calyx
absent or of 4 or 5 scalelike, free sepals, usually shed as the flower opens.
Corollas of 3–6(–8) free petals, broadly tubular or slightly
urn-shaped, the petals somewhat pouched at the base, rounded to truncate at the
tip. Stamens 6–10, in 2 whorls, not exserted, the outer whorl shorter
than the inner whorl, the filaments attached between the pairs of lobes of a
prominent nectary disk, usually hairy, the anthers without spurs or appendages,
dehiscing by sometimes irregular slits across the tip. Ovary with (4)5(6)
locules, superior, the placentation axile. Style 2–3 mm long, stout,
straight, enlarging slightly and persistent at fruiting, the stigma obconic or
disk-shaped, (4)5-lobed. Fruits capsules, globose to ovoid, the surface with
shallow, longitudinal grooves, brown at maturity, dehiscing longitudinally.
Seeds numerous, 0.8–1.2 mm long, 0.1–0.2 mm wide, very narrowly
ellipsoid, tapered to a tail-like tip at each end, the surface smooth, light
brown. Two species, North America to South America, Europe, Asia.
Monotropa and related genera are one of several
groups of angiosperms known variously as saprophytes, mycotrophic plants, and
epiparasites. In Missouri, the other main group of such organisms occurs in the
Orchidaceae. These strange-looking plants have lost their chlorophyll and
capacity for photosynthesis, deriving their water and nutrients via soilborne
fungi that have established a mycorrhizal relationship with their roots (hence
the term mycotrophic). The roots are individually poorly developed and
are often clustered into dense, irregularly spherical masses of short roots.
The term saprophyte is somewhat misleading, as plants of Monotropa
do not, of themselves, derive sustenance directly from decaying organic matter.
Instead, the fungal intermediates provide water and nutrients from decay
processes and from tree species growing in the vicinity. In experiments
involving the injection of radioisotopically labeled substances into the phloem
of trees, Björkman (1960) demonstrated the passage of sugars and phosphates
from the trees to Monotropa. This has given rise to the designation epiparasite,
in recognition of the secondary parasitism of tree species via fungal connections,
which is different from the true parasitism of plants such as mistletoes (Phoradendron,
Viscaceae) that form direct connections with the vascular system of their
Species of Monotropa
have been used as an eye tonic, sedative, analgesic, and general tonic, among
other medicinal uses.